Etiologic factors in progression of carotid stenosis: a 10-year study in 905 patients

Purpose: The purpose of this study was to determine the etiologic factors in the progression of carotid stenosis. Methods: We performed prospective serial duplex scan surveillance of 1470 carotid arteries in 905 asymptomatic patients during a 10-year period, with an average follow-up interval of 29 months and an average of 3.0 scans per carotid artery. Vascular laboratory and hospital records were used to collect risk factor information. The data were analyzed with proportional hazards modeling. Results: We examined several demographic, clinical, and laboratory risk factors that were chosen because of their potential relevance to atherosclerotic disease. These factors were analyzed with univariate proportional hazards modeling, in which time to progression of stenosis was the outcome variable. The six significant predictors (P < .05) were age, sex, systolic pressure, pulse pressure (systolic pressure – diastolic pressure), total cholesterol, and high-density lipoprotein (HDL). All, except HDL, were positive predictors of time to disease progression. With multivariate modeling, only pulse pressure and HDL remained as significant independent predictors of stenosis progression. The risk ratio for a 10–mm Hg rise in pulse pressure was 1.12, and the risk ratio for a 10-mg/dL decrease in HDL was 1.20. Conclusion: In this large cohort of patients who were followed prospectively for carotid stenosis, pulse pressure and HDL were found to be the key risk factors for carotid stenosis progression. The fact that pulse pressure superseded systolic pressure in multivariate modeling may shed light on the biology of carotid plaque progression. Further, our identification of these modifiable risk factors may help in the design of therapeutic trials for the prevention of progression of carotid atherosclerosis. (J Vasc Surg 2000;31:31-8.)